Pliers having ratchet fastening mechanism

Abstract

A fastening mechanism mounted in a pair of pliers comprises a pawl mechanism including an internal gear member and peripheral latched pieces, a peripheral ratchet inside a hole in one pliers with pawl mechanism disposed therein for catching and holding one of the latched pieces in a first position, a pivot joint having a circumferential gear member meshed with the gear member of pawl mechanism, an elastic member put on the joint, and a fastening member urged by the elastic member being secured to the joint. In gripping, the pawl mechanism is allowed to move in only one direction such that a release of the gripping on handles does not disengage a gripped object from the jaws in a second position. In releasing, press the fastening member to compress the elastic member for disengaging the pawl mechanism from the ratchet prior to returning to the first position once compression of the elastic member is released.

What is claimed is:  
     
         1 . A fastening mechanism mounted in a pair of first and second pliers comprising: 
 an aperture formed in the second pliers;    a cylindrical pawl mechanism including a stage bore, an internal gear member formed on an upper surface of the bore, and a plurality of peripheral latched pieces;    a peripheral ratchet inside a hole in the first pliers with the pawl mechanism disposed therein so as to catch and hold one of the latched pieces in a first position;    a joint for pivotably coupling the pliers and having a circumferential gear member meshed with the gear member of the pawl mechanism in the first position wherein the joint inserts through the aperture and the bore of the pawl mechanism;    an elastic member put on the joint;    a fastening member urged by the elastic member being releasably secured to the joint; and    a torsion spring anchored between the pliers;    wherein in an operation of gripping an object between jaws of the pliers, the torsion spring is compressed, the pawl mechanism is allowed to move in only a first direction such that a release of the gripping on handles of the pliers does not disengage the object from the jaws in a second position; and in an operation of releasing the object, the fastening member is operative to compress the elastic member so as to disengage the gear member of the joint from the gear member of the pawl mechanism, disengage the pawl mechanism from the ratchet, and expand the torsion spring for returning to the first position once the compression of the elastic member is released.    
     
     
         2 . The fastening mechanism of  claim 1 , wherein the gear member of the pawl mechanism has sloped teeth and the gear member of the joint has corresponding sloped teeth.  
     
     
         3 . The fastening mechanism of claim  1 I wherein each of the latched pieces comprises a cavity for spacing the latched piece from the pawl mechanism and a tooth on an outer side disposed corresponding to one of a plurality of teeth of the ratchet.